Field of the Invention
The present invention concerns a method and a magnetic resonance system for acquiring MR data in a volume segment of an examination subject.
Description of the Prior Art
In order to acquire MR data, magnetic field gradients are switched (activated), among other things. Considerable current intensities occur when the magnetic field gradients are switched. Because the gradient coils, with which the magnetic field gradients are generated, are located within the main magnetic field (B0 field) of the magnetic resonance system, this causes a Lorentz force to be generated that leads to a mechanical excitation of the gradient coil system of the magnetic resonance scanner. When there is a rapid change in the magnetic field gradients, and hence a rapid change in the Lorentz forces, this results in strong vibrations of the entire structure of the magnetic resonance scanner, and such vibrations can also be transmitted via the ambient air. As a consequence, different levels of loudness exposure are produced, depending on the applied rate of rise or speed of rise (slew rate) of the magnetic field gradients. The loudness generally increases logarithmically with the slew rate of the respective gradient.